Demolition firing device



Feb. 11, 1964 R. G. ESHLEMAN ETAL 3,120,310

I DEMOLITION FIRING DEVICE Filed Dec. 6, 1961 5 Sheets-Sheet 1 INVENTORS. JAMES W. FARMER RALPH G. ESHLEMAN AGENT 1964 R. G. ESHLEMAN ETAL 3,

DEMOLITION FIRING DEVICE Filed Dec. 6, 1961 s Sheets-Sheet 2 INVENTORS. JAMES W. FARMER RALPH G. ESHLEMAN a)? AGENT.

Feb. 11, 1964 R. G. ESHLEMAN ETAL 3,120,310

DEMOLITION FIRING DEVICE Filed Dec. 6, 1961 3 Sheets-Sheet 3 INVENTORS. JAMES W. FARMER RALPH G. ESHLEMAN I f ATTYS. l nr AGENT 3 United States Patent O 3,120,810 DEMOLITION FIRING DEVICE Ralph G. Eshleman and James W. Farmer, Lancaster, Pa., assignors, by mesne assignments, to the United States of America as represented by the Secretary of the Navy Filed Dec. 6, 1961, Ser. No. 157,606 Claims. (Cl. 102-84) This invention relates to a timed, mechanical detonating mechanism for a fuze or the like, and more particularly to a mechanism for setting a desired time-delay and for arming such a device. The general purpose of this invention is to provide a watertight, rugged mechanical detonating mechanism which may be pre-set to any desired time; which is safe or unarmed before and during the setting operation; and which provides an automatic mechanical means for arming the device, starting the timing mechanism and mechanically detonating the device.

To attain this result, the present invention contemplates a unique arming shaft assembly and a starting lever assembly, both cooperating with a central time setting shaft in such a manner that after the desired time is set, a safing fork may be pulled releasing the central setting shaft which allows the device to automatically arm and start the timing mechanism.

It is, therefore, an object of the invention to provide a watertight, time-delay, detonating mechanism which is safe or unarmed during the setting operation.

A further object of the invention is to provide an arming shaft assembly which is automatically released when a safing fork is removed from the central setting shaft.

A further object is the provision of a spring loaded lever assembly to provide the necessary mechanical power for arming the device when the safing fork is removed.

Still another object is to provide a starting lever assem bly to prevent any movement of the timing mechanism and unwinding of the mainspring prior to arming of the device and which cooperates with the central setting shaft mechanism to start the clock mechanism when the device is aimed.

Yet another object is the provision of a suitable watertight housing for the device which lends itself to ease in manufacture and assembly, yet provides the necessary structure to protect the device.

Other objects and many of the attendant advantages iof the invention will be more readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings in which like reference numerals designate like parts throughout the figures thereof and wherein:

FIG. 1 is a sectional view of the device partially broken away and taken along line 1-1 of FIG. 2;

FIG. 2 is a section of the device taken along line 22 of FIG. 1 before insertion of the central setting shaft;

FIG. 3 is a partial section of the device taken along line 3--3 of FIG. 2 illustrating the pillar system utilized in the construction of the device;

FIG. 4 is a cross section of the device taken along line 4--4 of FIG. 1 illustrating the safety rotor in the unarmed or safe position;

FIG. 5 is a partial section taken along line 5-5 of FIG. 1 illustrating the starting lever assembly; and

FIG. 6 is a partial inverted view of FIG. 5 as indicated by the arrows 6-6.

As illustrated in FIG. 1 the device has a casing 11, an upper external plate 12, a lower external plate 13, a retaining ring 14 abutting the casing and secured to the lower external plate by any suitable means, such, for example, as a plurality of radially spaced screws, not shown, the casing being sealed by a pair of O-rings 15.

3,120,813 Patented Feb. 11, 1964 An upper internal plate 16 and a lower internal plate 17 are secured to the external plates by a conventional pillar system 18 as best illustrated in FIG. 3. Secured to the upper external plate 12 is a setting shaft collar 19 having a pair of holes adapted to receive a conventional bifurcated safing fork 21 in the well known manner.

The timing and triggering unit 22 is divided into a stationary portion 23 and a rotating portion 24, the stationary portion being secured within the recess in the lower internal plate 17 by the ring 25 and the plurality of suitable screw means 26. Bearing 27 allows relative movement between the stationary portion 23 and the rotating portion 24 of the timing and triggering unit 22 and the upper internal plate 16 serves as a second hearing surface for the rotating portion 24. Secured to the upper end of the rotating portion 24 is a clockwork mechanism 28 which serves as an escapement and regulator for the unwinding of a main-spring contained within the rotating portion as it drives the barrel arbor 20 in any well known manner, such, for example, so that illustrated in US. Patent 2,640,418. 7

Spring loaded firing pin 29 contained within the tin ing and triggering unit 22 is restrained from movement by lever 31 which is pivoted for rotational movement at pivot 32, but restrained therefrom by cam follower arbor 33. Cam follower arbor 33 has a groove 34 therein and is pivotally secured within the stationary portion 23. Secured to cam follower arbor 33 is a radially extending arm 35 having a pin 36 therein engaging the spiral groove 37 contained in the annular plate 38. Cam follower arbor 33 is biased for rotational movement by spring 39 and is restrained therefrom by pin 36 engaging groove 37 in plate 38. Annular plate 38 is secured to the lower end of barrel arbor 213 which rotates within rotating portion 24 under control of the timing escapement 28. As barrel arbor 20 and annular plate 38 rotate under control of the escapement mechanism, the radially extending arm is allowed to pivot until pin 36 reaches the outer end of the spiral groove 37. When pin 36 reaches the outer end of spiral groove 37, the spring 39 rotates the radially extending arm 35 outwardly away from plate 38 in such a manner that groove 34 in the cam follower arbor 33 allows lever 31 to pass through the groove 34 thereby releasing the lever 31. Lever 31 pivots about its pivot 32 due to the force applied to the lever by the beveled portion of firing pin 29 and the firing pin is released.

Secured for rotatable movement in the upper external plate 12 and the setting shaft collar 19 is a setting shaft 41 for rotating rotating portion 24 and the barrel arbor 20 and plate 38 secured thereto and having an annular groove 42 therein for receiving the safing fork 21, a setting shaft pin 43 extending through the setting shaft, and a setting shaft extension 44 which holds the starting lever 45 from rotational movement for reasons which will hereinafter become more readily apparent as the description proceeds. The setting shaft 41 is sealed within the upper external plate and setting shaft collar by 'O-ring 46 and is restrained from axial movement by the safing fork 21 engaging the setting shaft about the annular groove 42. Secured for pivotal movement to the upper external plate 12 is a lever 47 having a bifurcated portion at one end thereof extending around the central setting shaft 41 and bearing against a disc 48 secured to the setting shaft 41. Spring 49 is secured at one end to the lower internal plate 17 and at the other end to the lever 47 in such a manner that the bifurcated portion of lever 47 bears against disc 4-8 and tends to drive the setting shaft 41 outwardly,

Secured to the clockwork mechanism 28 is a dial 51 having aplurality of numbers thereon and a slot 52 for receiving the setting pin 43 and allowing the central shaft extension 44 to extend therethrough. When the device is in the unarmed condition, as illustrated in FIG. 1, the pin 43 engages the dial 51 along the slot 52 and locks the rotating portion 24 of timing and triggering unit 22 to the setting shaft 41 for rotational movement. As the setting shaft is rotated to set the desired time-delay period as indicated by the numerals on the dial 51, pin 36 is positioned in the spiral groove 37 on annular plate 3 8 to obtain the desired time-delay as hereinbefore described.

Secured to the clockwork mechanism 28 below the dial 51 is the starting lever pivoted at point 53 and biased by spring 54. Starting lever 45 is restrained from movement by the central shaft extension 44 as best illustrated in FIG. 5. The starting lever 45 has a whisker 55 which engages the rim of the clockwork mechanism balance wheel 56 as best illustrated in FIG. 6, and restrains the balance wheel from movement during the period when the device is unarmed.

Referring now to FIGS. 1 and 4 there is illustrated a safety rotor 57 pivoted for rotational movement at 58 and biased by spring 59. Safety rotor 57 is held in the safe or unarmed position by the arming shaft 61 pivotally secured between the upper and lower external plates 12 and 13 and biased for rotational movement by arming shaft spring 62. Rotor 57 has a blind or through hole 60 therein that is coaxial with the firing pin when the rotor is in the safe or unarmed position illustrated in FIG. 4. If the firing pin 29 is prematurely released, the firing pin engages the safety rotor to restrain it from movement to the armed position as will hereinafter become more readily apparent as the description proceeds. Arming shaft 61 has a slot 63 aligned with the safety rotor 57 in such a manner that when the arming shaft is rotated the slot therein allows the safety rotor to swing past the arming shaft to the position indicated by the dashed lines in FIG. 4 thereby removing the safety rotor from beneath the firing pin 29 and arming the device. The arming shaft 61 is held from rotational movement by safety arming shaft control lever 64 bearing against the disc 48 located on the setting shaft 41.

Firing pin aperture 65 is sealed by a thin, gilding metal diaphragm 66 held in place by screw-in-plug 67 adapted to receive a priming device, and sealed by 'O-ring 68.

Within the upper external plate 12 is a window positioned above the indicator adjacent the dial 51 comprising a lens 69 which is secured in place by washer 70 screwed to the under side of plate 12 and sealed by O-ring 50. The window has been rotated from above the indicator in FIG. 2 to the section of FIG. 1 for illustration.

The device is assembled in the unarmed or safe condition as illustrated in each of the figures, e.g., the safety rotor 57 is positioned below the firing pin 29, the setting pin 43 is engaged in the dial slot 52, and whisker 55 frictionally engages the balance wheel 56 thereby preventing movement of the clockwork mechanism 28. The time-delay period is set by rotating the setting shaft 41 until the numeral corresponding to the desired time-delay on dial 5l is opposite the indicator within the Window 69. This action rotates the annular plate 38 secured to the barrel arbor 20 and positions the pin 36 on the radially extending arm 35 within the spiral groove 37. To arm the device the safing fork 21 is pulled out of the setting shaft collar 19 thereby releasing the central setting shaft 41. The setting shaft is driven outwardly by spring 49 and the bifurcated lever 47 hearing against the disc 48. The outward movement of the setting shaft 41 moves the disc 43 past the safety arming shaft control lever 64, releasing the arming shaft 61 which is rotated by the arming shaft spring 62 until slot 63 is positioned in such a manner that the safety rotor 57 is released. Safety rotor 57 pivots about the pivot 58 due to the safety rotor spring 59 to the armed position indicated by the dashed lines in FIG. 4 thereby removing the safety rotor from beneath the firing pin 29. Simultaneously with this action the central shaft extension 44 has moved past the starting lever 45 freeing it for rotational movement about the starting lever pivot 53. The starting lever 45 rotates due to the bias of spring 54 removing the whisker 55 from engagement with the balance wheel 56 and at the same time imparting to the balance wheel a slight rotational movement to insure starting of the clockwork mechanism 28. When starting lever 45 has moved to the armed position, it constitutes a barrier preventing return of central shaft 41 to the setting position. This makes it impossible to alter the setting of the armed device since pin 43 cannot be engaged with slot 52.

The mainspring, contained within the timing and triggering unit 22 as hereinbefore described, starts to drive the barrel arbor 259, this rotational movement being regulated by the clockwork mechanism 28. As has been hereinbefore described, the firing pin 29 is restrained from movement by the lever 31 pivoted at 32, and bearing against the beveled portion of the firing pin 29 and cam follower arbor 33. As the annular plate 38 secured to the barrel arbor 20 rotates, the pin 36 follows the spiral groove 37 in the annular plate until it reaches the end thereof at which time the spring 33 secured to the radially extending arm 35 rotates the cam follower arbor 33 until groove 34 allows the lever 31 to pivot about 32. The beveled portion of firing pin 29 pushes lever 31 aside and firing pin 29 is released. Since the safety rotor 57 is now in the position indicated by the dashed lines in PEG. 4, the firing pin 29 is driven through the gilding metal diaphragm 66 allowing the firing pin to strike the priming device which has been secured in the screw-inplug 67 thereby detonating the device.

There has been illustrated and described a completely mechanical time-delay firing mechanism which until armed restrains any movement of the timing mechanism, which allows simple and accurate setting of the desired time-delay while the device is in the unarmed condition, and when armed, provides a positive impulse to the clockwork mechanism to insure starting of the timing unit.

It should be understood, of course, that the foregoing disclosure relates to only a preferred embodiment of the invention and that numerous modifications or alterations may be made therein without departing from the spirit and scope of the invention as set forth in the appended claims.

What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. A normally unarmed demolition time-delay firing device comprising a spring driven, regulated timing mechanism, manually settable means to determine a time in terval rotated by said mechanism, a spring loaded firing pin, means controlled by said timing mechanism for re leasing said firing pin after said time interval, means cooperating With said settable means for arming the device, and means connected to said timing mechanism for restraining said timing mechanism from movement while the device is unarmed and for providing a positive starting impulse to said timing mechanism when said device is armed.

2. The firing device of claim 1 wherein said last named means is a spring biased, pivotable lever having a Whisker in frictional contact with a balance Wheel in said timing mechanism.

3. A demolition firing device capable of being set for a predetermined firing time after arming of the device comprising a regulated, settable timing mechanism, a normally locked firing pin, means controlled by said timing mechanism for releasing said firing pin after a predetermined interval of time, means engaging said timing mechanism and settable to a setting corresponding to said predetermined interval of time, normally locked spring loaded safety means pivotally mounted in such a manner as to restrict the movement of said firing pin should said firing pin be released before said interval of time begins, and means connected to said second named means and said safety means to unlock said safety means and allow the safety means to pivot to an ineffective position when said interval of time begins.

4. The firing device of claim 3 wherein said second named means is a first rotatable shaft axially movable from an unarmed position to an armed position, a disc on said first shaft, a spring loaded lever bearing against said disc tending to drive said first shaft to said armed position, arming means engaging and holding said first shaft in the unarmed position until the arming means is removed, and said third named means is a spring loaded shaft biased for rotational movement and having a slot therein, a control arm secured to said spring loaded shaft and engaging said disc and restraining movement of said spring loaded shaft when said first shaft is in the unarmed position, whereby when said arming means is removed, said first shaft is driven to the armed position and said spring loaded shaft rotates until the slot therein allows said safety means to pivot to the ineffective position.

5. The firing device of claim 4 further comprising means connected to said timing mechanism and said first rotatable shaft to restrain said timing mechanism from movement when said first rotatable shaft is in the unarmed position and to impart a positive starting impulse to said timing mechanism when said first rotatable shaft is moved to the armed position.

6. The firing device of claim 5 wherein said last named means is a lever biased for movement about a pivot and restrained therefrom by said first rotatable shaft when in the unarmed position, a whisker on said lever, said whisker normally engaging the periphery of a balance wheel Within said timing mechanism.

7. In a demolition firing device having a firing pin and a timing mechanism capable of being set for a predetermined time-delay to release the firing pin, the improvement comprising a first shaft movable from an armed position to an unarmed position, means for engaging said first shaft to restrain the timing mechanism from movement when said first shaft is in the unarmed position and for providing a positive starting impulse to said mechanism when said first shaft moves to the armed position, and means connected to said first shaft to restrict movement of the firing pin should the firing pin be released while said first shaft is in the unarmed position.

8. The device of claim 7 wherein said first named eans is a lever pivotally mounted on the timing mechanism, a whisker on said lever initially engaging the timing mechanism in such a manner so as to prevent movement thereof, a spring secured to said lever and to the timing mechanism in such a manner as to tend to cause said lever to pivot and thereby providing a positive release impulse to the timing mechanism when said shaft moves to the armed position.

9. The device of claim 8 wherein said second named means comprises a spring biased rotor movable from an unarmed position to an armed position, said rotor tending to move to the armed position, a second spring biased rotatable shaft having a groove therein adjacent said biased rotor, a control arm secured to said second shaft and first shaft, said control arm restraining said second shaft from rotation when said first shaft is in the unarmed position, said second shaft restraining movement of said rotor when said first shaft is in the unarmed position, whereby when said first shaft moves to the armed position said second shaft rotates until the groove therein releases said rotor.

10. A settable time-delay mechanical demolition firing device comprising a first external plate and a second external plate, each of said plates having an aperture therein, a collar adapted to receive a safing fork secured to said first external plate, a first internal plate and a second internal plate spatially supported between said first and second external plates, said first and second internal plates each having an aperture therein, a settable timing and triggering unit comprising a spring loaded firing pin mounted in a release mechanism, a barrel housing assembly and a clockwork escapement assembly supported by said first and second internal plates, a first rotatable shaft extending through said collar and the aperture in said first external plate, said first rotatable shaft being movable from an unarmed position to an armed position, a pin extending through said first shaft and engaging said timing and triggering unit when said first shaft is in the unarmed position whereby when said first shaft is rotated said timing mechanism is set to a desired time period, a disc secured to said first shaft, a bifurcated lever pivotally secured to said first external plate and engaging said disc, a spring secured to said second internal plate and to said lever in such a manner that said lever tends to move said first shaft to the armed position, a detachable safing fork engaging said collar and said first shaft to hold said first shaft in the unarmed position until said safing fork is removed, means supported by said timing and triggering unit and engaging said timing mechanism to prevent movement thereof when said first shaft is in said unarmed position, means connected to said first named means and to said timing and triggering unit to disengage said first named means from said timing mechanism and to impart a positive starting pulse thereto when said first shaft moves to said armed position, a second rotatable shaft supported by said first and second external plates, a radially extending arm secured to said second shaft and engaging said disc when said first shaft is in the unarmed position, means secured to said second shaft and to said first external plate for rotating said second shaft when said first shaft moves to the armed position, a safety rotor pivotally secured to said second external plate, said rotor being movable from an unarmed position to an armed position, means tending to pivot said rotor to the armed position, said second shaft engaging said rotor to restrain movement thereof when said first shaft is in said unarmed position, said second shaft having a groove therein for releasing said rotor when said first shaft moves to the unarmed position, receptacle means holding a primer device secured to said second external plate, frangible means cooperating with said last named means and said second external plate for sealing the aperture in said second external plate, a cylindrical housing secured to said first nad second external plates, and means for sealing said housing to said first and second external plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,777,547 Bold Oct. 7, 1930 2,448,228 McCaslin et al. Aug. 31, 1948 2,453,479 Whitehead Nov. 9, 1948 2,821,925 Varaud Feb. 4, 1958 2,895,419 Rosselet July 21, 1959 2,911,915 Gibbs Nov. 10, 1959 3,030,887 Simmen et al Apr. 24, 1962 FOREIGN PATENTS 284,968 Great Britain Feb. 9, 1928 

1. A NORMALLY UNARMED DEMOLITION TIME-DELAY FIRING DEVICE COMPRISING A SPRING DRIVEN, REGULATED TIME MECHANISM, MANUALLY SETTABLE MEANS TO DETERMINE A TIME INTERVAL ROTATED BY SAID MECHANISM, A SPRING LOADED FIRING PIN, MEANS CONTROLLED BY SAID TIMING MECHANISM FOR RELEASING SAID FIRING PIN AFTER SAID TIME INTERVAL, MEANS COOPERATING WITH SAID SETTABLE MEANS FOR ARMING THE DEVICE, AND MEANS CONNECTED TO SAID TIMING MECHANISM FOR RESTRAINING SAID TIMING MECHANISM FROM MOVEMENT WHILE THE DEVICE IS UNARMED AND FOR PROVIDING A POSITIVE STARTING IMPULSE TO SAID TIMING MECHANISM WHEN SAID DEVICE IS ARMED. 